What Slows Down Shopify Stores the Most?

Too many third-party apps, unoptimized heavy images, and bloated theme code are the primary factors that slow down Shopify stores, as they increase network requests, block rendering, and add unnecessary load to both server and browser performance.

Speed is the primary factor to attract customers and for conversion, and depends on how optimized overall Shopify store setup is.

Let's discuss in detail.

Excessive Apps and Third-Party Scripts

No doubt, Shopify apps and Google Analytics are useful. They add upsells, personalization, and marketing automation. But each app often injects extra JavaScript, additional CSS, external server calls, and tracking scripts that slow down page loading.

Premium themes are usually optimized. Issues arise when we upload assets without optimization or allow unoptimized apps. Analyze what is truly important for your Shopify store. If we will not consider what happens behind the scene and how it will be handled delicately, page will face the issue of speed.

Moreover, many apps continue loading scripts even if their functionality isn't used on a specific page. Deferring non-critical JavaScript like analytics and tracking pixels, social media widgets and buttons, and chat widgets allows basic elements like text, images, and buttons to load first.

How to Fix:

• Audit apps regularly and remove unused ones
• Replace heavy apps with lightweight custom code where possible
• Load scripts conditionally only where needed
• Use async/defer for third-party scripts

Unoptimized Heavy Images

High-quality photos are important for product display. However, neglecting image optimization makes heavy images one of the biggest reasons for a Shopify store becoming slow. Uploading high-resolution images without compression and using unoptimized, older formats like PNG should be avoided for better store performance.

Unoptimized heavy images not only impact Largest Contentful Paint (LCP), a key Core Web Vital, but also affect First Contentful Paint (FCP), Interaction to Next Paint (INP), and Time to Interactive (TTI).

What helps in reducing file size while maintaining visual quality:

• Resizing
• Compressing
• Using modern formats like WebP

Bloated Theme Code

Shopify themes use Liquid, Shopify's templating language. While Liquid works efficiently, many stores use heavily customized themes that add excessive, unnecessary HTML, CSS, and JavaScript in a website theme. These elements make it harder for the browser to render a heavy, unoptimized website efficiently.

To reduce theme bloat, it is important to:

• Remove unused sections, templates, and snippets
• Simplify Liquid logic and avoid excessive loops
• Minify and split CSS and JavaScript files
• Load scripts conditionally instead of globally
• Reduce DOM complexity by simplifying layouts

At DevSplit, we identify and fix the real causes. Let's turn your sluggish store into a high-speed selling machine.